CSS3背景
???1.背景图像区域
???????background-clip 属性 指定背景绘制区域
???????语法：background-clip:boder-box|padding-box|content-box
???????????boder-box： 从边框盒的地方绘制图像，边框盒外的被裁剪
???????????padding-box：从内边距盒开始绘制背景图像，内边距外的被裁剪
???????????contrnt-box：从内容部分开始绘制背景图像，内容外的被裁剪
???????IE9+ FireFox Chrome Safari Opera
???2.背景图像定位
???????background-origin属性 指定background-position属性应该是相对位置
???????????设置元素背景图片的原始起始位置
???????????background-position定义的是背景图像的位置，有两个值，水平和垂直偏移量，都是以左上角为坐标原点
???????????具体左上角是什么位置就是由background-origin指定
???????语法：background-origin:boder-box|padding-box|content-box
???????????????????boder-box： 从边框盒的左上角
???????????????????padding-box：从内边距盒左上角
???????????????????contrnt-box：从内容部分左上角
???????IE9+ FireFox4+ Chrome Safari5+ Opera
???3.CSS3背景图片的大小
???????background-size 指定背景图片的大小
???????语法： background-size:length|percentage|cover|contin
???????????????????????/*将背景图片等比缩放至某一边紧贴容器边缘为止*/
???????????????????????background-size:contain ;
???????????????????????/*将背景图片等比缩放以填满整个容器*/
???????????????????????background-size: cover;
???????????????????????background-size: 800px 500px;
???????????????????????background-size: 800px;
???????????????????????background-size: 50% 50%;
???????????????????????background-size: 50%;
???????????????????????background-size: 100% 100%;
???????????????????????/*背景图像宽度是div宽度的100%，高度根据背景图片宽度和高度的原始比例缩放*/
???????????????????????background-size: 100% ;
???????兼容：IE9+ FireFox4+ Chrome Safari5+ Opera
???多重背景图像
???????为元素使用多个背景图
???????语法 background-image:url(img1.jpg),url(img2.png);
???????元素引用多个背景图片时，前面的图片一次覆盖后面图
???背景属性整合
???????背景缩放属性可以在一个声明中设置所有的背景属性
???????语法：background:color position size repeat origin clip attachment image
???????????color position size repeat(是否重复) origin（起始位置） clip（区域） attachment（图片状态 是随页面滚屏还是固定不动）
<!DOCTYPE html><html lang="en"><head> ???<meta charset="UTF-8"> ???<title>背景图像定位</title> ???<style type="text/css"> ???????*{ ???????????margin: 0; ???????????padding: 0; ???????????border:none; ???????} ???????div{ ???????????width: 800px; ???????????height: 400px; ???????????padding: 50px; ???????????/*transparent半透明*/ ???????????border: 50px solid transparent; ???????????/*background:color position size repeat origin clip attachment image*/ ???????????background:red center 50% no-repeat content-box content-box fixed url("java.png") ?; ???????????/*background-origin: border-box;*/ ???????????/*background-origin:padding-box;*/ ???????????/*!*权重最后一个会超越前两个*!*/ ???????????/*background-origin:content-box;*/ ???????????background: green url("java.png") no-repeat center center ; ???????????background-size:50% ; ???????????background-origin: content-box; ???????????background-clip: content-box; ???????????background-attachment: fixed; ???????} ???????/*通过绝对位置虚拟div边框*/ ???????span.div_border{ ???????????position: absolute; ???????????top: 0; ???????????left: 0; ???????????width: 800px; ???????????height: 400px; ???????????padding: 50px; ???????????border: 50px solid rgba(255,0,0,.25); ???????} ???????/*虚拟div填充*/ ???????span.div_padding{ ???????????position: absolute; ???????????top: 50px; ???????????left: 50px; ???????????width: 800px; ???????????height: 400px; ???????????border: 50px solid rgba(63, 255, 52, 0.25); ???????} ???</style></head><body><div></div><span class="div_border"></span><span class="div_padding"></span></body></html>
CSS3背景
原文地址：https://www.cnblogs.com/alasijia/p/9223462.html